Imaging system, lens device, and method of operating lens device

ABSTRACT

A first imaging unit images angle-of-view mark light of each of other television cameras. An image compositing unit generates a virtual angle-of-view mark image and a virtual angle-of-view frame image as a virtual angle-of-view image showing an imaging angle of view of each of the other television cameras in an imaging angle of view of the host television camera based on the angle-of-view mark light of each of the other television cameras. The image compositing unit generates a composite image by compositing the virtual angle-of-view mark image and the virtual angle-of-view frame image with a video image. The composite image is displayed on a lens monitor of a lens device that is detachable from a camera body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of PCT International Application No.PCT/JP2016/088190 filed on 21 Dec. 2016, which claims priority under 35U.S.C. § 119(a) to Japanese Patent Application No. 2016-006586 filed on15 Jan. 2016. The above application is hereby expressly incorporated byreference, in its entirety, into the present application.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an imaging system, a lens device, and amethod of operating a lens device.

2. Description of the Related Art

Imaging in a studio at a broadcasting station is performed using animaging system that includes a plurality of television cameras (imagingdevices) imaging a subject at the same time. As disclosed inJP2000-106647A, the imaging system includes a video switching device(referred to as a switcher) that selects a plurality of video imagesgenerated by the television cameras. The selected video images areeither output as an on-air image to a broadcasting device or output as arecording image to a recording device.

In JP2000-106647A, an evaluation value indicating the state of anautomatic control system that automatically controls exposure and colorreproduction is generated for each of the plurality of televisioncameras, and an optimal control value for imaging the subject iscalculated based on the evaluation value. The automatic control systemof each television camera is controlled using the optimal control value.Accordingly, it is possible to prevent variations in exposure and colorrepresentation for the subject among the plurality of televisioncameras.

SUMMARY OF THE INVENTION

A cameraman who operates a television camera decides a composition inthe host television camera in accordance with the composition in anothertelevision camera in order not to make a viewer feel uncomfortable.Thus, a television camera is typically provided with a function ofdisplaying a video image of another television camera in order for thecameraman to check the video image imaged by the other televisioncamera. However, a function of checking the composition in the hosttelevision camera and the composition in the other television camera atthe same time is not provided. Thus, a delay may be caused in decidingthe composition in the host television camera in accordance with thecomposition in the other television camera, and a video image that isnot switched in time using a video switching device and thus, makes theviewer feel uncomfortable may be output.

Some television camera may include a camera body and a lens device thatis detachably attached to the camera body and replaceable. In a casewhere a function of checking the composition in the other televisioncamera and the composition in the host television camera at the sametime is provided in the camera body in such a television camera of whichthe lens device is replaceable, all existing camera bodies have to bereplaced with new ones, and cost is increased.

An object of the invention is to provide an imaging system, a lensdevice, and a method of operating a lens device that enable a pluralityof video images generated by a plurality of imaging devices to besmoothly switched at a reduced cost without making a viewer feeluncomfortable.

In order to achieve the object, an imaging system of the invention is animaging system comprising a plurality of imaging devices that image asubject at the same time. Each imaging device includes a camera body anda lens device that is detachably attached to the camera body. The lensdevice has an imaging lens, an extracting unit, a first imaging unit, animage compositing unit, and a lens monitor. On the imaging lens, subjectlight including angle-of-view mark light that is emitted from otherimaging devices and that shows an imaging angle of view of each of theother imaging devices is incident. The extracting unit extracts theangle-of-view mark light from the subject light. The first imaging unitimages the angle-of-view mark light and outputs a first imaging signalfor detecting the angle-of-view mark light. The image compositing unitgenerates a virtual angle-of-view image showing the imaging angle ofview of each of the other imaging devices in an imaging angle of view ofthe host imaging device based on the first imaging signal, and generatesa composite image by compositing the virtual angle-of-view image with avideo image acquired by imaging the subject light after theangle-of-view mark light is removed by the extracting unit. The lensmonitor displays the composite image.

It is preferable that the lens device includes a mark light detectingunit that detects the angle-of-view mark light based on the firstimaging signal, and a calculating unit that calculates a position of avirtual angle-of-view mark showing the imaging angle of view of each ofthe other imaging devices in the imaging angle of view of the hostimaging device based on the angle-of-view mark light. It is preferablethat the image compositing unit generates the virtual angle-of-viewimage that corresponds to the position of the virtual angle-of-viewmark.

It is preferable that the lens device has a mark light source that emitsthe angle-of-view mark light. In this case, it is preferable that thefirst imaging unit is an imaging unit for focus control that controls afocus of the imaging lens to be at a focused position. It is preferablethat the mark light source is disposed in the first imaging unit. It ispreferable that the angle-of-view mark light serves as light for thefocus control and is emitted toward the subject through the imaginglens.

It is preferable that in addition to the virtual angle-of-view image,the image compositing unit composites, with the video image, a changedisplaying image that shows a change in the virtual angle-of-view imageat the current point in time from the virtual angle-of-view image beforea certain time period from the current point in time.

It is preferable that a light emitting pattern of the angle-of-view marklight is different for each of the plurality of imaging devices. It ispreferable that the light emitting pattern is any one of a turn-on andturn-off interval, a light emission intensity, and a projection shape.

It is preferable that in a case where the virtual angle-of-view imagesof two or more of the other imaging devices are composited, the imagecompositing unit displays the virtual angle-of-view image in a differentform for each of the other imaging devices.

It is preferable that the lens device includes an operating unit thatselects an imaging device for which the virtual angle-of-view image isto be generated from the other imaging devices, and that the imagecompositing unit composites the virtual angle-of-view image of theimaging device selected by the operating unit.

It is preferable that the imaging system further comprises a videoswitching device that selects one video image from a plurality of thevideo images generated by the plurality of imaging devices and outputsthe selected video image to an external device, and that the imagecompositing unit composites only the virtual angle-of-view image of theimaging device of which the video image is selected by the videoswitching device among the other imaging devices.

It is preferable that the imaging angle of view has a rectangular shape,and that the angle-of-view mark light has a projection shape along twoorthogonal straight lines constituting a corner of the imaging angle ofview.

It is preferable that the angle-of-view mark light is light in awavelength range different from visible light.

It is preferable that the camera body has a camera monitor, and that thecomposite image is also displayed on the camera monitor.

A lens device of the invention is a lens device detachably attached to acamera body of an imaging device used in an imaging system that includesa plurality of imaging devices imaging a subject at the same time. Thelens device comprises an imaging lens, an extracting unit, an imagingunit, an image compositing unit, and a lens monitor. On the imaginglens, subject light including angle-of-view mark light that is emittedfrom other imaging devices and that shows an imaging angle of view ofeach of the other imaging devices is incident. The extracting unitextracts the angle-of-view mark light from the subject light. Theimaging unit images the angle-of-view mark light and outputs an imagingsignal for detecting the angle-of-view mark light. The image compositingunit generates a virtual angle-of-view image showing the imaging angleof view of each of the other imaging devices in an imaging angle of viewof the host imaging device based on the imaging signal, and generates acomposite image by compositing the virtual angle-of-view image with avideo image acquired by imaging the subject light after theangle-of-view mark light is removed by the extracting unit. The lensmonitor displays the composite image.

A method of operating a lens device of the invention is a method ofoperating a lens device detachably attached to a camera body of animaging device used in an imaging system that includes a plurality ofimaging devices imaging a subject at the same time. The method comprisesan extracting step, an imaging step, an image compositing step, and adisplaying step. In the extracting step, an extracting unit extractsangle-of-view mark light that is emitted from other imaging devices andthat shows an imaging angle of view of each of the other imagingdevices, from subject light including the angle-of-view mark light. Inthe imaging step, an imaging unit images the angle-of-view mark lightand outputs an imaging signal for detecting the angle-of-view marklight. In the image compositing step, an image compositing unitgenerates a virtual angle-of-view image showing the imaging angle ofview of each of the other imaging devices in an imaging angle of view ofthe host imaging device based on the imaging signal, and generates acomposite image by compositing the virtual angle-of-view image with avideo image acquired by imaging the subject light after theangle-of-view mark light is removed by the extracting step. In thedisplaying step, the composite image is displayed on a lens monitor.

According to the invention, the composite image of the video image andthe virtual angle-of-view image showing the imaging angle of view ofeach of the other imaging devices in the imaging angle of view of thehost imaging device is displayed on the lens monitor of the lens device.Thus, it is possible to provide an imaging system, a lens device, and amethod of operating a lens device that enable a plurality of videoimages generated by a plurality of imaging devices to be smoothlyswitched at a reduced cost without making a viewer feel uncomfortable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a state where a subject is being imagedby two television cameras at the same time in a studio.

FIG. 2 is a diagram illustrating an internal configuration of an imagingsystem and a television camera.

FIG. 3 is a front view illustrating a pupil-splitting lens and a marklight source.

FIG. 4 is a diagram illustrating a composite image.

FIG. 5 is a flowchart illustrating a procedure of subject imaging usingthe television camera.

FIG. 6 is a diagram illustrating display of a virtual angle-of-viewimage in a different form for each television camera.

FIG. 7 is a diagram illustrating compositing of only the virtualangle-of-view image of the television camera selected by a switchingswitch.

FIG. 8 is a diagram illustrating compositing of only the virtualangle-of-view image of the television camera for which a video image isselected by a video switching device.

FIG. 9 is a diagram illustrating angle-of-view mark light having anL-shaped projection shape.

FIG. 10A, FIG. 10B, and FIG. 10C are diagrams illustrating angle-of-viewmark light having various projection shapes.

FIG. 11 is a diagram illustrating angle-of-view mark light having alattice projection shape.

FIG. 12 is a diagram illustrating a composite image acquired bycompositing a change displaying image that shows a change in imagingangle of view caused by a zooming operation.

FIG. 13 is a diagram illustrating a composite image acquired bycompositing a change displaying image that shows a change in imagingangle of view caused by a pan operation.

FIG. 14 is a perspective view illustrating an example in which a marklight source is disposed outside a television camera.

FIG. 15 is a diagram illustrating a second embodiment in which acomposite image is displayed on a camera monitor in a camera body.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

FIG. 1 illustrates a state where a subject is being imaged by a firsttelevision camera 11A and a second television camera 11B as imagingdevices at the same time in a studio 7. In the following description,reference numbers related to the first television camera 11A will besuffixed with “A”, and reference numbers related to the secondtelevision camera 11B will be suffixed with “B” for distinction. Unlessotherwise required for distinction, the letters “A” and “B” will not beadded in description.

The first television camera 11A and the second television camera 11Bhave an imaging angle of view 8A and an imaging angle of view 8B,respectively. Each of the imaging angle of view 8A and the imaging angleof view 8B has a rectangular shape. Angle-of-view mark light 9A thatshows the imaging angle of view 8A is emitted to the four corners of theimaging angle of view 8A. Similarly, angle-of-view mark light 9B thatshows the imaging angle of view 8B is emitted to the four corners of theimaging angle of view 8B. The projection shape of each of theangle-of-view mark light 9A and the angle-of-view mark light 9B is acircular shape. In the case illustrated in FIG. 1, the centers of theimaging angle of views 8A and 8B match approximately, and a person H ispresent in the matching position. The imaging angle of view 8B is widerthan the imaging angle of view 8A.

The angle-of-view mark light 9 is light in a wavelength range differentfrom visible light, for example, infrared light. Visible light is lightin a wavelength range of approximately 400 nm to 750 nm. Infrared lightincludes near-infrared light of 750 nm to 2.5 jam, mid-infrared light of2.5 μm to 50 μm, and far-infrared light of 50 μm or longer. Thus, forexample, infrared light in a wavelength range of 750 nm to 1,500 nm isused as the angle-of-view mark light 9. Visible light in a wavelengthrange of 650 nm to 750 nm that is close to the infrared region may alsobe used as the angle-of-view mark light 9.

The television camera 11 includes a lens device 12 and a camera body 13.The lens device 12 is detachably attached to the camera body 13 to becapable of being replaced with another lens device 12. A lens monitor 14is installed in the lens device 12. A camera monitor 15 is installed inthe camera body 13.

In FIG. 2, the first television camera 11A and the second televisioncamera 11B constitute an imaging system 2 along with a video switchingdevice 37 and the like. The first television camera 11A and the secondtelevision camera 11B have completely the same internal configuration.Thus, in FIG. 2, only the internal configuration of the first televisioncamera 11A is illustrated, and the internal configuration of the secondtelevision camera 11B is not illustrated.

The lens device 12 has an imaging lens 16 and a controller 17. Subjectlight is incident on the imaging lens 16. The subject light includes theperson H, the floor and the wall of the studio 7, and also theangle-of-view mark light 9 in the imaging angle of view 8. The imaginglens 16 has, for example, a fixed-focus lens 21, a moving focus lens 22,a zoom lens 23, a variable stop (iris) 24, a front relay lens 25, adichroic mirror 26, and a rear relay lens 27 in this order from thesubject side. The fixed-focus lens 21, the moving focus lens 22, thezoom lens 23, the variable stop 24, the front relay lens 25, thedichroic mirror 26, and the rear relay lens 27 have a matching opticalaxis O1. The moving focus lens 22 can move along the optical axis O1.The zoom lens 23 has lenses 28 and 29 of a magnification changing systemand a correction system. In FIG. 2, the configuration of each lens issimplified, and a lens group composed of a plurality of lenses isillustrated as one lens.

The controller 17 controls the position of the moving focus lens 22, theposition of the zoom lens 23, and the F number of the variable stop 24.The lens monitor 14 and an operating unit 31 are connected to thecontroller 17. The lens monitor 14 includes a liquid crystal panel. Thelens monitor 14 displays a graphic screen and the like showing the stateof various settings of the lens device 12. In addition, the lens monitor14 displays a composite image 55 (refer to FIG. 4) as will be describedlater. The operating unit 31 has an operating key and an operating knob(not illustrated). Various settings of the lens device 12 can be set byoperating the operating key and the operating knob while viewing thelens monitor 14.

The camera body 13 has a second imaging unit 18 and an image processingunit 19. The second imaging unit 18 images the subject light incidentfrom the lens device 12 and outputs a second imaging signal for video.The second imaging unit 18 has a color separating optical system 32 andthree video imaging elements 33, 34, and 35. The color separatingoptical system 32 separates the subject light into red light, greenlight, and blue light of three colors. Each of the video imagingelements 33 to 35 includes a solid-state imaging device such ascharged-coupled devices (CCD) or a complementarymetal-oxide-semiconductor (CMOS). The video imaging elements 33 to 35convert the light of three colors separated by the color separatingoptical system 32 into the second imaging signal.

The image processing unit 19 performs a predetermined process on thesecond imaging signal output from the video imaging elements 33 to 35 togenerate a video image. The image processing unit 19 transmits the videoimage to the camera monitor 15. The camera monitor 15 displays the videoimage as a through-image (live view). In addition, the image processingunit 19 transmits the video image to an image compositing unit 53 of thelens device 12.

The image processing unit 19 also transmits the video image to the videoswitching device 37. Two switcher monitors 38A and 38B are connected tothe video switching device 37. The switcher monitor 38A displays thevideo image from the first television camera 11A. The switcher monitor38B displays the video image from the second television camera 11B. Astaff member who operates the video switching device 37 observes eachvideo image displayed on the switcher monitors 38A and 38B and operatesthe video switching device 37 to select the video image that has adesired composition. Accordingly, each video image from the firsttelevision camera 11A and the second television camera 11B is switchedat an appropriate timing and output as an on-air image or a recordingimage to an external device 39 that is a broadcasting device or arecording device.

The video switching device 37 transmits information on the televisioncamera 11 of the selected video image to each of the television cameras11A and 11B. The television camera 11 of the selected video imageinforms the person H that the video image is selected by, for example,lighting an on-air lamp included in the camera body 13.

The dichroic mirror 26 is disposed to be inclined at an angle ofapproximately 45 degrees with respect to the optical axis O1 between thefront relay lens 25 and the rear relay lens 27 that constitute a relayoptical system. The dichroic mirror 26 reflects the angle-of-view marklight 9 of the subject light and transmits light of the subject lightother than the angle-of-view mark light 9. In the present embodiment,since the angle-of-view mark light 9 is infrared light in a wavelengthrange of 750 nm to 1,500 nm, the dichroic mirror 26 reflects infraredlight in a wavelength range of 750 nm to 1,500 nm and transmits otherlight, for example, visible light in a wavelength range of approximately400 nm to 750 nm. That is, the dichroic mirror 26 functions as anextracting unit that extracts the angle-of-view mark light 9 from thesubject light. The subject light after the angle-of-view mark light 9 isremoved by the dichroic mirror 26 is guided to the second imaging unit18 in the camera body 13 along the optical axis O1. Meanwhile, theangle-of-view mark light 9 is reflected by the dichroic mirror 26 at anangle of 90 degrees and is guided to a pupil-splitting phase-differenceautomatic focusing device 40 along an optical axis O2 that is orthogonalto the optical axis O1.

The automatic focusing device 40 has a first imaging unit 41 and a focuscontroller 42. The first imaging unit 41 has a mark light source 43, apupil-splitting lens 44, a light screen 45, and a focus sensor 46. Thepupil-splitting lens 44 is disposed in positions in the light screen 45that correspond to a plurality of pupil regions in an exit pupil of theimaging lens 16. The focus sensor 46 includes an imaging element thatreacts to the angle-of-view mark light 9 and converts the angle-of-viewmark light 9 into an electric signal. The angle-of-view mark light 9that passes through the pupil-splitting lens 44 is imaged by the firstimaging unit 41 using the focus sensor 46, and the first imaging unit 41outputs a first imaging signal. The first imaging unit 41 outputs thefirst imaging signal to the focus controller 42 and a mark lightdetecting unit 47.

The focus controller 42 has a focus position calculating unit 48. Thefocus position calculating unit 48 detects a deviation (defocus amount)of the focus of the imaging lens 16 based on the first imaging signalfrom the focus sensor 46. The focus controller 42 moves the moving focuslens 22 along the optical axis O1 such that the defocus amount becomesequal to “0”. Accordingly, automatic focus control is performed to set afocused position. The first imaging unit 41 is an imaging unit for focuscontrol that controls the focus of the imaging lens 16 to be at thefocused position. The first imaging signal is used for detecting theangle-of-view mark light and is also used for focus control. Theangle-of-view mark light 9 serves as light for focus control. Thecalculation of the defocus amount using phase difference based on pupilsplitting, and the focus control based on the defocus amount are wellknown and thus, will not be described in detail.

As illustrated in FIG. 3, the light screen 45 has four mark lightsources 43 and four pupil-splitting lenses 44. The pupil-splittinglenses 44 are disposed at equal intervals in the upper, lower, left, andright parts of the light screen 45. Each mark light source 43 isdisposed between the adjacent pupil-splitting lenses 44. Each mark lightsource 43 includes a light emitting diode (LED) or a laser.

In FIG. 2, a light source driver 49 is connected to each mark lightsource 43. Each mark light source 43 emits the angle-of-view mark light9 in a predetermined light emitting pattern under control of the lightsource driver 49. The angle-of-view mark light 9 emitted from each marklight source 43 is guided to the dichroic mirror 26 along the opticalaxis O2 and is reflected by the dichroic mirror 26 at an angle of 90degrees. Then, the angle-of-view mark light 9 passes through the imaginglens 16 along the optical axis O1 and is emitted toward the subject inthe studio 7 as illustrated in FIG. 1. In a case where the angle-of-viewmark light 9 hits the subject, reflective light is guided to the focussensor 46 through the imaging lens 16, the dichroic mirror 26, and eachpupil-splitting lens 44.

A light emitting pattern changing unit 50 of the controller 17 isconnected to the light source driver 49. The light emitting patternchanging unit 50 is provided with, for example, 10 types of lightemitting patterns from a memory 51. Each light emitting pattern has adifferent turn-on and turn-off interval (light emission ON-OFF time)and/or a light emission intensity. The light emitting pattern changingunit 50 sets one light emitting pattern that is selected from the 10types of light emitting patterns by the cameraman or the like throughthe operating unit 31. The light source driver 49 controls each marklight source 43 such that the angle-of-view mark light 9 is emitted inthe light emitting pattern set by the light emitting pattern changingunit 50.

Different light emitting patterns are set for the angle-of-view marklight 9A and the angle-of-view mark light 9B. By identifying the lightemitting patterns of the angle-of-view mark light 9A and theangle-of-view mark light 9B, it is possible to specify whether theemission source of the angle-of-view mark light 9 is the mark lightsource 43 of the television camera 11A or the mark light source 43 ofthe television camera 11B. Accordingly, by specifying the emissionsource of the angle-of-view mark light 9, the imaging angle of views 8Aand 8B of the television cameras 11A and 11B can be estimated.

In the present embodiment, each mark light source 43 is disposed betweenthe pupil-splitting lenses 44 as illustrated in FIG. 3. Since each marklight source 43 emitting the angle-of-view mark light 9 is disposedseparately from each pupil-splitting lens 44 that receives theangle-of-view mark light 9, the angle-of-view mark light 9 can beemitted to the four corners of the imaging angle of view 8 asillustrated in FIG. 1 without hindering each pupil-splitting lens 44from receiving the angle-of-view mark light 9. The angle-of-view marklight 9 from each mark light source 43 is emitted toward the subjectthrough the imaging lens 16 that includes the zoom lens 23. Accordingly,regardless of the zoom magnification of the imaging lens 16, theangle-of-view mark light 9 can be emitted to certain positions close tothe four corners of the imaging angle of view 8 at all times. Inaddition, regardless of not only the zoom magnification but also thedistance to the subject, the angle-of-view mark light 9 can be emittedto certain positions close to the four corners of the imaging angle ofview 8 at all times.

In the state illustrated in FIG. 1, the subject light that includes onlythe angle-of-view mark light 9A of the host first television camera 11Ais incident on the imaging lens 16A of the first television camera 11A.Meanwhile, the subject light that includes the angle-of-view mark light9B of the host second television camera 11B and also the angle-of-viewmark light 9A from the first television camera 11A is incident on theimaging lens 16B of the second television camera 11B. Each of theangle-of-view mark light 9A and the angle-of-view mark light 9B isinfrared light in a wavelength range different from visible light, andis reflected by the dichroic mirror 26 and not guided to the secondimaging unit 18. Thus, the angle-of-view mark light 9A and theangle-of-view mark light 9B do not affect the second imaging signaloutput from the second imaging unit 18.

The mark light detecting unit 47 detects the angle-of-view mark light 9based on the first imaging signal from the first imaging unit 41.Specifically, an area that emits light in a certain light emittingpattern in the image based on the first imaging signal is detected asthe angle-of-view mark light 9. Based on the light emitting pattern, themark light detecting unit 47 specifies whether the detectedangle-of-view mark light 9 is emitted from the mark light source 43 ofthe host television camera 11 or emitted from the mark light source 43of another television camera 11. A correspondence between each lightemitting pattern of the angle-of-view mark light 9 and each televisioncamera 11 for which each light emitting pattern is set is stored in thememory 51. The mark light detecting unit 47 specifies the emissionsource of the angle-of-view mark light 9 by referencing thiscorrespondence. The mark light detecting unit 47 outputs the result ofdetection of the angle-of-view mark light 9 and the result of specifyingthe emission source of the angle-of-view mark light 9 to a calculatingunit 52.

The calculating unit 52 calculates the position of a virtualangle-of-view mark showing the imaging angle of view 8 of the othertelevision camera 11 in the imaging angle of view 8 of the hosttelevision camera 11 based on the result of detection of theangle-of-view mark light 9 of the mark light detecting unit 47. Apositional relationship between the image based on the first imagingsignal and the imaging angle of view 8 of the host television camera 11is stored in advance in the memory 51. The calculating unit 52 performsthe calculation by referencing this correspondence. The position of thevirtual angle-of-view mark is the projection position of theangle-of-view mark light 9 of the other television camera 11 that ispresent in the imaging angle of view 8 of the host television camera 11.For example, in the state illustrated in FIG. 1, the calculating unit52B of the second television camera 11B calculates the position of thevirtual angle-of-view mark (the projection position of the angle-of-viewmark light 9A) showing the imaging angle of view 8A of the firsttelevision camera 11A in the imaging angle of view 8B of the host secondtelevision camera 11B based on the result of detection of theangle-of-view mark light 9A. The calculating unit 52 transmits thecalculated position of the virtual angle-of-view mark to the imagecompositing unit 53.

The calculating unit 52 acquires a virtual angle-of-view frame showingthe frame of the imaging angle of view 8 of the other television camera11 based on the position of the virtual angle-of-view mark.Specifically, the virtual angle-of-view frame is specified from arectangular frame that includes line segments connecting the virtualangle-of-view mark. The calculating unit 52 outputs the result ofspecifying the virtual angle-of-view frame to the image compositing unit53.

The calculating unit 52 calculates only the position of the virtualangle-of-view mark based on the angle-of-view mark light 9 from theother television camera 11, and does not calculate the position of thevirtual angle-of-view mark for the angle-of-view mark light 9 of thehost television camera 11. For example, in the state illustrated in FIG.1, while the angle-of-view mark light 9B of the host second televisioncamera 11B is present in the imaging angle of view 8B of the host secondtelevision camera 11B, the calculating unit 52B of the second televisioncamera 11B does not calculate the position of the virtual angle-of-viewmark for the angle-of-view mark light 9B. The same applies to thevirtual angle-of-view frame, and the calculating unit 52 does notspecify the virtual angle-of-view frame of the host television camera11. Whether or not the angle-of-view mark light 9 is from the hosttelevision camera 11 is determined from the result of specifying theemission source of the angle-of-view mark light 9 from the mark lightdetecting unit 47.

The image compositing unit 53 generates a virtual angle-of-view imagethat corresponds to the position of the virtual angle-of-view mark andthe virtual angle-of-view frame from the calculating unit 52. The imagecompositing unit 53 composites the virtual angle-of-view image with thevideo image based on the second imaging signal from the second imagingunit 18 to generate the composite image. The image compositing unit 53outputs the generated composite image to the lens monitor 14. The lensmonitor 14 displays the composite image as a through-image.

FIG. 4 illustrates a composite image 55B displayed on the lens monitor14B of the second television camera 11B in the state illustrated inFIG. 1. The composite image 55B is acquired by compositing the videoimage that is imaged by the second television camera 11B and has theperson H and the floor and the wall of the studio 7, with a virtualangle-of-view mark image 56A and a virtual angle-of-view frame image 57Aas the virtual angle-of-view image. The virtual angle-of-view mark image56A shows the angle-of-view mark light 9A from the first televisioncamera 11A. The virtual angle-of-view frame image 57A shows the frame ofthe imaging angle of view 8A of the first television camera 11A. Thevirtual angle-of-view mark image 56A has the same circular shape as theprojection shape of the angle-of-view mark light 9.

A cameraman of the second television camera 11B can easily find thecurrent composition of imaging performed by the second television camera11B and also the current composition of imaging performed by the firsttelevision camera 11A by viewing the composite image 55B through thelens monitor 14B. Accordingly, the cameraman of the second televisioncamera 11B can immediately decide the composition in the secondtelevision camera 11B in accordance with the composition in the firsttelevision camera 11A, and can image a video image that does not make aviewer feel uncomfortable with respect to the video image of the firsttelevision camera 11A using the second television camera 11B.

While illustration is not provided, the angle-of-view mark light 9B fromthe second television camera 11B is not emitted to the inside of theimaging angle of view 8A of the first television camera 11A in the stateillustrated in FIG. 1. Thus, the virtual angle-of-view mark image 56Bshowing the angle-of-view mark light 9B, and the virtual angle-of-viewframe image 57B showing the frame of the imaging angle of view 8B arenot composited in the composite image 55A displayed on the lens monitor14A of the first television camera 11A. That is, the composite image 55Ais the video image based on the second imaging signal from the secondimaging unit 18A of the first television camera 11A.

Hereinafter, the effect of the imaging system 2 and a method of imagingin the studio 7 using the imaging system 2 in the present embodimentwill be described with reference to a flowchart in FIG. 5. First, thetelevision camera 11 is started up, and imaging of the subject using thetelevision camera 11 is started. The subject light is incident on theimaging lens 16. The angle-of-view mark light 9 is emitted toward thesubject from each mark light source 43 (step ST10).

In the subject light incident on the imaging lens 16, light except theangle-of-view mark light 9 is transmitted through the dichroic mirror 26and guided to the second imaging unit 18. The angle-of-view mark light 9is reflected by the dichroic mirror 26 and guided to the first imagingunit 41 (step ST11; extracting step). In the second imaging unit 18, thesubject light after the angle-of-view mark light 9 is removed is imaged,and the second imaging signal is output (step ST12). The second imagingsignal is converted into a video image by the image processing unit 19.Meanwhile, in the first imaging unit 41, the angle-of-view mark light 9is imaged, and the first imaging signal is output (step ST13; imagingstep). The first imaging signal is used for focus control performed bythe focus controller 42, and is also output to the mark light detectingunit 47.

In the mark light detecting unit 47, the angle-of-view mark light 9 isdetected based on the first imaging signal (step ST14). In addition, theemission source of the angle-of-view mark light 9 is specified based onthe light emitting pattern of the angle-of-view mark light 9 (stepST15). The result of detection of the angle-of-view mark light 9 and theresult of specifying the emission source of the angle-of-view mark light9 are output to the calculating unit 52.

In the calculating unit 52, the position of the virtual angle-of-viewmark is calculated, and the virtual angle-of-view frame is specifiedbased on the result of detection of the angle-of-view mark light 9 (stepST16). At this point, only the position of the virtual angle-of-viewmark and the virtual angle-of-view frame based on the angle-of-view marklight 9 from the other television camera 11 are calculated andspecified. The result of calculation of the position of the virtualangle-of-view mark, and the result of specifying the virtualangle-of-view frame are transmitted to the image compositing unit 53.

In the image compositing unit 53, the virtual angle-of-view mark image56 and the virtual angle-of-view frame image 57 are generated as thevirtual angle-of-view image. The virtual angle-of-view mark image 56 andthe virtual angle-of-view frame image 57 are composited with the videoimage that is subjected to image processing by the image processing unit19 (step ST17; image compositing step). In the image compositing, thevirtual angle-of-view mark image 56 is composited at the projectionposition of the angle-of-view mark light 9 of the other televisioncamera 11 based on the result of calculation of the position of thevirtual angle-of-view mark from the calculating unit 52. In addition,based on the result of specifying the virtual angle-of-view frame, thevirtual angle-of-view frame image 57 is composited on the frame of theimaging angle of view 8 of the other television camera 11 thatcorresponds to the projection position of the angle-of-view mark light9. The composite image 55 is displayed on the lens monitor 14 asillustrated in FIG. 4 (step ST18; displaying step). In a case where theangle-of-view mark light 9 of the other television camera 11 is notdetected in steps ST14 and ST15 as in the first television camera 11A ofthe present embodiment, steps ST16 and ST17 are not performed, and thevideo image is displayed on the lens monitor 14.

Since the virtual angle-of-view image (the virtual angle-of-view markimage 56 and the virtual angle-of-view frame image 57) showing theimaging angle of view 8 of the other television camera 11 in the imagingangle of view 8 of the host television camera 11 is composited with thevideo image, and the generated composite image 55 is displayed on thelens monitor 14, the cameraman recognizes the composition of imaging inthe other television camera 11 at the same time as the composition inthe host television camera 11 by viewing the composite image 55displayed on the lens monitor 14. Thus, there is no delay in decidingthe composition for the cameraman, and a video image that is notswitched in time using the video switching device 37 and thus, makes theviewer feel uncomfortable is not output. Accordingly, the video imagecan be smoothly switched without making the viewer feel uncomfortable.

All functional units of the lens monitor 14, the mark light detectingunit 47, the calculating unit 52, and the image compositing unit 53 thatgenerate and display the composite image 55 are disposed in the lensdevice 12. Thus, the composition in the other television camera 11 canbe checked by replacing only the lens device 12 of the invention withoutreplacing the existing camera body 13. Accordingly, the function ofchecking the composition in the other television camera 11 and thecomposition in the host television camera 11 at the same time can beintroduced in the existing television camera 11 at a low cost.

The video image needs to be transmitted to the image compositing unit 53of the lens device 12 from the image processing unit 19 in the camerabody 13. Since a terminal for outputting the video image to the outsideis generally disposed in the camera body 13, the video image may betransmitted to the image compositing unit 53 using the terminal. Thus,the camera body 13 does not need a special modification.

Since a light source for focus control disposed in the first imagingunit 41 that is an imaging unit for focus control is used as the marklight source 43, and light for focus control is used as theangle-of-view mark light 9, an existing light source for focus controlthat is generally included in the television camera 11 can beeffectively used. Since a dedicated light source for the angle-of-viewmark light 9 does not need to be disposed separately, product cost canbe reduced, and the television camera 11 can be made compact.

Since the angle-of-view mark light 9 is light in a wavelength rangedifferent from visible light, the angle-of-view mark light 9 does notflash and hinder imaging.

While the virtual angle-of-view image that includes the virtualangle-of-view mark image 56 and the virtual angle-of-view frame image 57is displayed on the lens monitor 14 in the first embodiment, the virtualangle-of-view image may include either the virtual angle-of-view markimage 56 or the virtual angle-of-view frame image 57. In addition, theshape of the virtual angle-of-view mark image 56 may be the same shape(in the present embodiment, a circular shape) as the projection shape ofthe angle-of-view mark light 9, or may be a different shape (in thepresent embodiment, a triangular shape, a quadrangular shape, otherpolygonal shapes, an L shape, and the like) from the projection shape ofthe angle-of-view mark light 9.

While the imaging system 2 that includes the two television cameras 11Aand 11B is illustrated in the embodiment, the imaging system may includethree or more television cameras 11. In this case, the number oftelevision cameras 11 other than the host television camera 11 isgreater than or equal to two. The image compositing unit 53 maycomposite the virtual angle-of-view images of all of the other two ormore television cameras 11. In this case, it is preferable to displaythe virtual angle-of-view image in a different form for each of theother television cameras 11 as illustrated in FIG. 6.

FIG. 6 is an example of a composite image 55C displayed on a lensmonitor 14C of a third television camera 11C (not illustrated) in theimaging system that includes three television cameras 11A, 11B, and 11C.The composite image 55C displays the virtual angle-of-view mark image56A showing the angle-of-view mark light 9A from the first televisioncamera 11A, the virtual angle-of-view frame image 57A showing the frameof the imaging angle of view 8A of the first television camera 11A, thevirtual angle-of-view mark image 56B showing the angle-of-view marklight 9B from the second television camera 11B, and the virtualangle-of-view frame image 57B showing the frame of the imaging angle ofview 8B of the second television camera 11B. The virtual angle-of-viewmark image 56A and the virtual angle-of-view frame image 57A are set tobe displayed in a different form from the virtual angle-of-view markimage 56B and the virtual angle-of-view frame image 57B using the nameof the television camera 11 as illustrated in FIG. 6, or by settingdifferent colors, different line types, and different thicknesses ofline, flashing either the virtual angle-of-view mark image 56A and thevirtual angle-of-view frame image 57A, or the virtual angle-of-view markimage 56B and the virtual angle-of-view frame image 57B, or the like. Bydisplaying the virtual angle-of-view image in a different form for eachof the other television cameras 11 in a case where the virtualangle-of-view images of the other two or more television cameras 11 arecomposited, the cameraman can distinguish the virtual angle-of-viewimages from each other at a glance.

Alternatively, the virtual angle-of-view image may be switched asdesired and displayed by disposing, in the operating unit 31, aswitching switch that selects the television camera 11 of which thevirtual angle-of-view image is to be composited from the othertelevision cameras 11, and causing the image compositing unit 53 tocomposite the virtual angle-of-view image of the television camera 11selected by the switching switch. The number of television cameras 11that can be selected by the switching switch may be one or more.Accordingly, the cameraman can recognize the composition in the othertelevision camera 11 that the cameraman desires to view.

FIG. 7 is an example of the composite image 55C displayed on the lensmonitor 14C of the third television camera 11C in the imaging systemthat includes the three television cameras 11A, 11B, and 11C as in FIG.6. The second television camera 11B is assumed to be selected by theswitching switch of the operating unit 31. In this case, the imagecompositing unit 53 does not composite the virtual angle-of-view markimage 56A and the virtual angle-of-view frame image 57A of the firsttelevision camera 11A that is not selected by the switching switch. Theimage compositing unit 53 composites only the virtual angle-of-view markimage 56B and the virtual angle-of-view frame image 57B of the secondtelevision camera 11B selected by the switching switch. Accordingly, thecomposite image 55C displays only the virtual angle-of-view mark image56B and the virtual angle-of-view frame image 57B unlike FIG. 6.

Alternatively, only the virtual angle-of-view image of the televisioncamera 11 of which the video image is selected by the video switchingdevice 37 may be composited as illustrated in FIG. 8.

FIG. 8 is an example of the composite image 55C displayed on the lensmonitor 14C of the third television camera 11C in the imaging systemthat includes the three television cameras 11A, 11B, and 11C as in FIG.6 and FIG. 7. The video image of the second television camera 11B isassumed to be selected by the video switching device 37. In this case,the image compositing unit 53 does not composite the virtualangle-of-view mark image 56A and the virtual angle-of-view frame image57A of the first television camera 11A that is not selected by the videoswitching device 37. The image compositing unit 53 composites only thevirtual angle-of-view mark image 56B and the virtual angle-of-view frameimage 57B of the second television camera 11B selected by the videoswitching device 37. Accordingly, the composite image 55C displays onlythe virtual angle-of-view mark image 56B and the virtual angle-of-viewframe image 57B unlike FIG. 6.

The television camera 11 in which the cameraman desires to check thecomposition first is the television camera 11 of which the video imageis currently selected by the video switching device 37. Thus, at leastthe object can be accomplished by compositing only the virtualangle-of-view image of the television camera 11 of which the video imageis selected by the video switching device 37. In addition, the compositeimage 55 is clearly displayed and easily viewed further than in a casewhere all of the virtual angle-of-view images of the other televisioncameras 11 are displayed as in FIG. 6.

MODIFICATION EXAMPLE 1

In a case where the angle-of-view mark light 9 has a shape that does nothave directivity such as a simple circular shape as in the firstembodiment, the imaging angle of view 8 cannot be correctly detectedfrom the angle-of-view mark light 9 in a case where the angle-of-viewmark light 9 is not detected at two of the four positions on the sameedge sides of the imaging angle of view 8, such as a case where theangle-of-view mark light 9 is emitted in an outdoor space where a wallor the like reflecting the angle-of-view mark light 9 is not present,and a case where the mark light source 43 fails to function. Thus, inModification Example 1, angle-of-view mark light 61, angle-of-view marklight 62, angle-of-view mark light 63, and angle-of-view mark light 64,each of which has an L-shaped projection shape along two orthogonalstraight lines constituting a corner of the imaging angle of view 8, areemitted to positions close to the four corners of the imaging angle ofview 8 as illustrated in FIG. 9. Instead of the L shape, each of theangle-of-view mark light 61 to the angle-of-view mark light 64 may havea shape in which the direction of the imaging angle of view 8 isindicated by one angle-of-view mark light, such as a right triangle(refer to FIG. 10A) that has two edges along the two orthogonal straightlines constituting the corner of the imaging angle of view 8.

In each of the L-shaped angle-of-view mark light 61 to the angle-of-viewmark light 64, lengths L1 and L2 of the edges are formed to be lengthsof a certain ratio with respect to a horizontal edge 59 and a verticaledge 60 of the imaging angle of view 8, for example, 1/10. Theprojection position of each of the angle-of-view mark light 61 to theangle-of-view mark light 64 is a position separated by L1 and L2 inwardsfrom each of the four corners of the imaging angle of view 8. In thisconfiguration, since the lengths of the horizontal edge 59 and thevertical edge 60 of the imaging angle of view 8 are found from thelength L1 along the horizontal edge 59 and the length L2 along thevertical edge 60, and the length L1 along the horizontal edge 59 isdifferent from the length L2 along the vertical edge 60, thecorrespondence between each of the L-shaped angle-of-view mark light 61to the angle-of-view mark light 64 and each of the four corners of theimaging angle of view 8 is found from the positional relationshipbetween the part having the length L1 and the part having the length L2.Accordingly, by detecting just one of the L-shaped angle-of-view marklight 61 to the angle-of-view mark light 64, the imaging angle of view 8can be correctly detected, and the virtual angle-of-view frame image 57can be correctly reproduced in the composite image 55.

The lengths L1 and L2 of the edges of each of the L-shaped angle-of-viewmark light 61 to the angle-of-view mark light 64 may be definedregardless of the horizontal edge 59 and the vertical edge 60 of theimaging angle of view 8. In this case, since the ratio (screen aspectratio) of the horizontal edge 59 to the vertical edge 60 of the imagingangle of view 8 is known, the imaging angle of view 8 can be correctlydetected in a case where two of the angle-of-view mark light 61 to theangle-of-view mark light 64 are detected. For example, in a case wherethe length of the vertical edge 60 is acquired by specifying thevertical edge 60, the horizontal edge 59 can be specified based on thescreen aspect ratio, and the virtual angle-of-view frame image 57 can becorrectly reproduced in the composite image 55. For example, in a casewhere the angle-of-view mark light 61 and the angle-of-view mark light63 close to the horizontal edge 59 on the upper side of the imagingangle of view 8, or the angle-of-view mark light 62 and theangle-of-view mark light 63 at the opposite corners of the imaging angleof view 8 are detected, the imaging angle of view 8 can be correctlydetected, and the virtual angle-of-view frame image 57 can be correctlyreproduced in the composite image 55.

MODIFICATION EXAMPLE 2

While the turn-on and turn-off interval and the light emission intensityare illustrated as the light emitting pattern of the angle-of-view marklight 9 changed for each television camera 11 in the first embodiment,the projection shape of the angle-of-view mark light 9 is changed foreach television camera 11 instead of or in addition to the turn-on andturn-off interval and the light emission intensity in ModificationExample 2. For example, as illustrated in FIGS. 10A, 10B, and 10C, theangle-of-view mark light from each television camera 11 is identifiedusing angle-of-view mark light 65, angle-of-view mark light 66, andangle-of-view mark light 67 having various projection shapes including atriangular shape, a quadrangular shape, and other polygonal shapes (astar shape in FIG. 10C) other than the angle-of-view mark having acircular shape as illustrated in FIG. 1. In this case, the emissionsource of the angle-of-view mark light can be specified based on theprojection shape of the angle-of-view mark light by extracting an areahaving a predetermined shape from the image based on the first imagingsignal.

MODIFICATION EXAMPLE 4

The angle-of-view mark light 9 is emitted to a certain position close toeach of the four corners of the imaging angle of view 8 in the firstembodiment. Instead or in addition, angle-of-view mark light 70 having alattice form is emitted in Modification Example 3 illustrated in FIG.11. The angle-of-view mark light 70 has a plurality of lattice lines 71that are parallel to the horizontal edge and the vertical edge of theimaging angle of view 8. The outermost frame of the angle-of-view marklight 70 is smaller than the frame of the imaging angle of view 8 ormatches the frame of the imaging angle of view 8. In this case, even ina case where a part of the lattice lines 71 of the angle-of-view marklight 70 is not reflected, the imaging angle of view 8 of the othertelevision camera 11 can be acquired by complementing the unreflectedlattice line 71 using the other reflected lattice lines 71. In addition,while illustration is not provided, the angle-of-view mark light may beemitted to not only the four corners of the imaging angle of view 8 butalso the center of the imaging angle of view 8. In this case, theimaging angle of view 8 is more easily specified.

MODIFICATION EXAMPLE 4

The composite image 55 in which the virtual angle-of-view mark image 56and the virtual angle-of-view frame image 57 are composited with thevideo image is displayed on the lens monitor 14 in the first embodiment.Meanwhile, in the composite image 55 of Modification Example 4illustrated in FIG. 12 and FIG. 13, arrows 75 and 76 as a changedisplaying image are also composited with the video image in addition tothe virtual angle-of-view mark image 56 and the virtual angle-of-viewframe image 57. The arrows 75 and 76 show the direction in which thecurrent virtual angle-of-view image is changed from the previous virtualangle-of-view image. The previous virtual angle-of-view image is thevirtual angle-of-view image before a certain time period (for example,approximately one to three seconds) from the current point in time. Thecurrent virtual angle-of-view image is the virtual angle-of-view imageat the current point in time.

In this case, the controller 17 stores, in the memory 51, the positionof the virtual angle-of-view mark before a certain time period that iscalculated by the calculating unit 52 (the position of a virtualangle-of-view mark image 56-0 illustrated by a dotted line in FIG. 12and FIG. 13; hereinafter, referred to as the position of a previousvirtual angle-of-view mark). The image compositing unit 53 compares theposition of the previous virtual angle-of-view mark stored in the memory51 with the position of the virtual angle-of-view mark at the currentpoint in time (the position of a virtual angle-of-view mark image 56-1illustrated by a solid line in FIG. 12 and FIG. 13; hereinafter,referred to as the position of a current virtual angle-of-view mark). Ina case where the position of the previous virtual angle-of-view mark isthe same as the position of the current virtual angle-of-view mark, theimage compositing unit 53 does not composite the arrows 75 and 76 as thechange displaying image. In a case where the position of the previousvirtual angle-of-view mark is different from the position of the currentvirtual angle-of-view mark, the image compositing unit 53 acquires thearrow 75 that is directed toward the position of the current virtualangle-of-view mark from the position of the previous virtualangle-of-view mark, and composites the arrow 75 with the video image. Inaddition to the arrow 75, the image compositing unit 36 composites thearrow 76 that shows the direction of change in the position of theimaging angle of view 8 (the position of a virtual angle-of-view frameimage 57-1 illustrated by a solid line in FIG. 12 and FIG. 13) at thecurrent point in time found from the position of the current virtualangle-of-view mark with respect to the position of the imaging angle ofview 8 (the position of a virtual angle-of-view frame image 57-0illustrated by a dotted line in FIG. 12 and FIG. 13) before a certaintime period found from the position of the previous virtualangle-of-view mark.

FIG. 12 illustrates a case where a zooming operation is performed by theother television camera 11. FIG. 13 illustrates a case where a panoperation is performed by the other television camera 11. By compositingthe arrows 75 and 76 as the change displaying image with the video imageand displaying the composite image 55, it is possible to easily find themost recent operation performed by the cameraman of the other televisioncamera 11. While the person H before the zooming operation or the panoperation is represented by a dotted line in FIG. 12 and FIG. 13, theperson H before the operation is not displayed in actuality. The floorand the wall of the studio 7 are not illustrated in FIG. 12 and FIG. 13.Only one of the arrows 75 and 76 may be displayed. The virtualangle-of-view mark image 56-0 and the virtual angle-of-view frame image57-0 may not be displayed.

While each mark light source 43 is disposed in the light screen 45 inthe embodiments, each mark light source 43 may be disposed in a lightscreening region formed by pupil splitting (outside a region where lightis transmitted by pupil splitting), or may be disposed at a positionoutside the light screen 45. While a plurality of pupil-splitting lenses44 is disposed in one light screen 45 in the embodiments, the lightscreen 45 may be split for each pupil-splitting lens 44 or for eachpupil-splitting group that includes several pupil-splitting lenses 44.The focus sensor 46 may also be disposed for each pupil-splitting lensor for each pupil-splitting group depending on the number of splits orthe state of arrangement of the pupil-splitting lenses 44.

MODIFICATION EXAMPLE 5

In the embodiments, each mark light source is disposed in the lightscreening region formed by pupil splitting. Instead, in ModificationExample 5 illustrated in FIG. 14, a mark light source 82 is disposedoutside a lens device 81 of a television camera 80, and angle-of-viewmark light 83 is emitted toward the subject. In this case, a deviationbetween the actual imaging angle of view 8 and the angle-of-view marklight 83 for showing the imaging angle of view 8 that is caused by theoptical axis O1 of the imaging lens 16 not matching the optical axis ofthe angle-of-view mark light 83 is adjusted. In Modification Example 5as well, the imaging angle of view 8 of the other television camera 11can be recognized in the same manner as the first embodiment.

Second Embodiment

The composite image 55 is displayed on the lens monitor 14 of the lensdevice 12 in the first embodiment. Instead or in addition, the compositeimage 55 is displayed on the camera monitor 15 in the camera body 13 ina second embodiment illustrated in FIG. 15. In this case, the compositeimage 55 of which the size is reduced is overlaid on the video imagebased on the second imaging signal displayed on the camera monitor 15.By doing so, the cameraman can recognize the composition in the othertelevision camera 11 from the camera monitor 15.

Alternatively, while illustration is not provided, the composite image55 may be displayed on the whole screen of the camera monitor 15 insteadof forming multiple screens by overlaying the reduced composite image 55on the video image as illustrated in FIG. 15.

The invention is not limited to the embodiments or modification examplesand may employ various configurations without departing from the natureof the invention. For example, the embodiments and the modificationexamples may be appropriately combined with each other.

The invention can be applied to other imaging devices such as a digitalcamera, a mobile phone, and a smartphone in addition to a televisioncamera.

EXPLANATION OF REFERENCES

7: studio

8, 8A, 8B: imaging angle of view

9, 9A, 9B, 61, 62, 63, 64, 65, 66, 67, 70, 83: angle-of-view mark light

11, 80: television camera

11A: first television camera

11B: second television camera

11C: third television camera

12, 81: lens device

13: camera body

14, 14A, 14B, 14C: lens monitor

15, 15A, 15B: camera monitor

16, 16A, 16B: imaging lens

17: controller

18: second imaging unit

19: image processing unit

21: fixed-focus lens

22: moving focus lens

23: zoom lens

24: variable stop

25: front relay lens

26: dichroic mirror (extracting unit)

27: rear relay lens

28, 29: lens

31: operating unit

32: color separating optical system

33, 34, 35: video imaging element

37: video switching device

38A, 38B: switcher monitor

39: external device

40: automatic focusing device

41: first imaging unit

42: focus controller

43, 82: mark light source

44: pupil-splitting lens

45: light screen

46: focus sensor

47: mark light detecting unit

48: focus position calculating unit

49: light source driver

50: light emitting pattern changing unit

51: memory

52, 52B: calculating unit

53: image compositing unit

55, 55A, 55B, 55C: composite image

56, 56A, 56B, 56-0, 56-1: virtual angle-of-view mark image (virtualangle-of-view image)

57, 57A, 57B, 57-0, 57-1: virtual angle-of-view frame image (virtualangle-of-view image)

59: horizontal edge

60: vertical edge

71: lattice line

75, 76: arrow (change displaying image)

H: person

O1, O2: optical axis

ST10 to ST18: step

L1, L2: lengths of edges of angle-of-view mark light

What is claimed is:
 1. An imaging system comprising a plurality ofimaging devices that image a subject at the same time, wherein eachimaging device includes a camera body, and a lens device that isdetachably attached to the camera body, and the lens device has animaging lens on which subject light including angle-of-view mark lightthat is emitted from other imaging devices and that shows an imagingangle of view of each of the other imaging devices is incident, anextracting unit that extracts the angle-of-view mark light from thesubject light, a first imaging unit that images the angle-of-view marklight and outputs a first imaging signal for detecting the angle-of-viewmark light, an image compositing unit that generates a virtualangle-of-view image showing the imaging angle of view of each of theother imaging devices in an imaging angle of view of the host imagingdevice based on the first imaging signal, and generates a compositeimage by compositing the virtual angle-of-view image with a video imageacquired by imaging the subject light after the angle-of-view mark lightis removed by the extracting unit, and a lens monitor that displays thecomposite image.
 2. The imaging system according to claim 1, wherein thelens device includes a mark light detecting unit that detects theangle-of-view mark light based on the first imaging signal, and acalculating unit that calculates a position of a virtual angle-of-viewmark showing the imaging angle of view of each of the other imagingdevices in the imaging angle of view of the host imaging device based onthe angle-of-view mark light, and the image compositing unit generatesthe virtual angle-of-view image that corresponds to the position of thevirtual angle-of-view mark.
 3. The imaging system according to claim 2,wherein the lens device has a mark light source that emits theangle-of-view mark light.
 4. The imaging system according to claim 3,wherein the first imaging unit is an imaging unit for focus control thatcontrols a focus of the imaging lens to be at a focused position, themark light source is disposed in the first imaging unit, and theangle-of-view mark light serves as light for the focus control and isemitted toward the subject through the imaging lens.
 5. The imagingsystem according to claim 1, wherein in addition to the virtualangle-of-view image, the image compositing unit composites, with thevideo image, a change displaying image that shows a change in thevirtual angle-of-view image at the current point in time from thevirtual angle-of-view image before a certain time period from thecurrent point in time.
 6. The imaging system according to claim 1,wherein a light emitting pattern of the angle-of-view mark light isdifferent for each of the plurality of imaging devices.
 7. The imagingsystem according to claim 6, wherein the light emitting pattern is anyone of a turn-on and turn-off interval, a light emission intensity, anda projection shape.
 8. The imaging system according to claim 6, whereinin a case where the virtual angle-of-view images of two or more of theother imaging devices are composited, the image compositing unitdisplays the virtual angle-of-view image in a different form for each ofthe other imaging devices.
 9. The imaging system according to claim 6,wherein the lens device includes an operating unit that selects animaging device for which the virtual angle-of-view image is to begenerated from the other imaging devices, and the image compositing unitcomposites the virtual angle-of-view image of the imaging deviceselected by the operating unit.
 10. The imaging system according toclaim 6, further comprising a video switching device that selects onevideo image from a plurality of the video images generated by theplurality of imaging devices and outputs the selected video image to anexternal device, wherein the image compositing unit composites only thevirtual angle-of-view image of the imaging device of which the videoimage is selected by the video switching device among the other imagingdevices.
 11. The imaging system according to claim 1, wherein theimaging angle of view has a rectangular shape, and the angle-of-viewmark light has a projection shape along two orthogonal straight linesconstituting a corner of the imaging angle of view.
 12. The imagingsystem according to claim 1, wherein the angle-of-view mark light islight in a wavelength range different from visible light.
 13. Theimaging system according to claim 1, wherein the camera body has acamera monitor, and the composite image is also displayed on the cameramonitor.
 14. A lens device detachably attached to a camera body of animaging device used in an imaging system that includes a plurality ofimaging devices imaging a subject at the same time, the lens devicecomprising: an imaging lens on which subject light includingangle-of-view mark light that is emitted from other imaging devices andthat shows an imaging angle of view of each of the other imaging devicesis incident; an extracting unit that extracts the angle-of-view marklight from the subject light; an imaging unit that images theangle-of-view mark light and outputs an imaging signal for detecting theangle-of-view mark light; an image compositing unit that generates avirtual angle-of-view image showing the imaging angle of view of each ofthe other imaging devices in an imaging angle of view of the hostimaging device based on the imaging signal, and generates a compositeimage by compositing the virtual angle-of-view image with a video imageacquired by imaging the subject light after the angle-of-view mark lightis removed by the extracting unit; and a lens monitor that displays thecomposite image.
 15. A method of operating a lens device detachablyattached to a camera body of an imaging device used in an imaging systemthat includes a plurality of imaging devices imaging a subject at thesame time, the method comprising: an extracting step in which anextracting unit extracts angle-of-view mark light that is emitted fromother imaging devices and that shows an imaging angle of view of each ofthe other imaging devices, from subject light including theangle-of-view mark light; an imaging step in which an imaging unitimages the angle-of-view mark light and outputs an imaging signal fordetecting the angle-of-view mark light; an image compositing step inwhich an image compositing unit generates a virtual angle-of-view imageshowing the imaging angle of view of each of the other imaging devicesin an imaging angle of view of the host imaging device based on theimaging signal, and generates a composite image by compositing thevirtual angle-of-view image with a video image acquired by imaging thesubject light after the angle-of-view mark light is removed by theextracting step; and a displaying step of displaying the composite imageon a lens monitor.